Massie, Dylan, Kristen and Alicia are the most popular girls at Octavian Country Day, calling themselves the Pretty Committee. However Massie is devastated when the Block family takes in the Lyons family, who have moved from Orlando, Florida with their teenage daughter, Claire. Claire attempts to impress Massie by convincing her mother to buy her designer clothing at the mall, where she bumps into Dylan and the two become acquainted. Meanwhile, Massie meets a boy named Chris Abeley while horseback riding and immediately finds him attractive. At school, Claire bumps into Chris in front of the steps, which makes Massie jealous. Massie orders the girls to exclude Claire because she had a fight with her. Claire meets the eccentric Layne Abeley, they become friends and eventually make plans on Friday. On Friday, Claire ditches Layne because Massie's mother invites Claire to Massie's weekend sleepover, but eventually leaves due to teasing. In the morning, Layne comes by to hang out with Claire and Chris tags along. He is revealed to be Layne's older brother. Massie holds a meeting for Kristen's project, which is to create a homemade makeup line called Glambition. They see Claire swimming in the pool and they tease her about her cheap bathing suit. Later that night, Claire goes to Massie's room to confront her but Massie is gone. In attempt to gain friends Claire Instant Messages Alicia, Kristen, and Dylan pretending to be Massie to drive the girls apart. When the Glambition makeup arrives, the girls get together to sort through the packages. They make snide comments at each other about their supposed dishonesty before realizing that Claire had manipulated all of them. They ambush Claire in a four way call and tell Claire that she doesn't belong there. Now friends again, the girls tell Massie that since the charity auction is on Chris' birthday, she should jump out of a pop out cake to impress him and Massie happily agrees. On a field trip to New York City, the Pretty Committee tries to sell their Glambition make up but their recipe contains peanut oil, which triggers allergic reactions in their classmates. In amidst the panic, Massie anonymously texts Claire to use Layne's oatmeal snack to reduce the swelling, which makes Claire a hero. At the charity auction, Claire meets Chris' girlfriend, Fawn and prevents Massie from jumping out of the cake. After the auction, Massie tells Claire that the reason why she had been mean was because she saw Claire as a threat. They mutually reconcile and both come to terms with their differences.
